Chicago — Attorney General Lisa Madigan and 14 other attorneys general, the California Air Resources Board, and the City of Chicago alerted the U.S. Environmental Protection Agency (EPA) today that they plan to sue if the agency continues to ignore its legal duty to control emissions of methane – an extremely potent greenhouse gas – from existing oil and gas operations.

In a letter today to EPA Administrator Scott Pruitt, the coalition provided the required notice of their intention to sue the agency for failing to fulfill its obligation under the Clean Air Act to control methane emissions from existing oil and natural gas sources and for "unreasonably delaying" the issuance of such controls.

"The U.S. EPA has an obligation to protect people and the environment from toxic methane pollution, and we will go into court if the agency continues to ignore this vital function," Madigan said.

Methane is an extremely potent greenhouse gas, warming the climate about 80 times more than carbon dioxide over a 20-year timeframe. Oil and gas operations – production, processing, transmission, and distribution – are the largest industrial source of methane emissions in the U.S. and the second largest industrial source of U.S. greenhouse gas emissions behind only electric power plants. Based on EPA data, the Environmental Defense Fund estimates that roughly $1.5 billion worth of natural gas – enough to heat over 5 million homes – leaks or is intentionally released from the oil and gas supply chain each year. The logic of continuing to allow leaks and intentional discharges of methane is especially dubious, as methane itself is a valuable product, being the primary component of natural gas.

In June 2016, EPA finalized standards to control methane emissions from oil and gas operations that were constructed or substantially modified after September 2015. Under the federal Clean Air Act, the regulation of these "new" sources triggered a legal requirement for the EPA also to regulate methane emissions from "existing" sources – emission sources in oil and gas operations in existence before September 2015.

In today's letter to Pruitt, the coalition argues that EPA's failure to act since September 2015 to issue controls on methane emissions from existing sources in the oil and gas industry violates the EPA's non-discretionary duty under the Clean Air Act and is an unreasonable delay in setting such controls.

Madigan and the coalition of attorneys general have taken several other steps to force the federal government to control methane pollution from the oil and gas industry. Last week, a coalition of 14 states filed a motion to intervene in a lawsuit against EPA's actions halting regulation of methane emissions from new sources in the oil and gas industry. In February, a coalition of seven attorneys general and two environmental agencies urged U.S. Senate leadership to oppose a Congressional Review Act resolution to repeal a rule regulating methane emissions from oil and gas operations on public lands.

Madigan also has condemned federal executive action to attempt to eliminate the Clean Power Plan and opposed the drastic budget cuts proposed for the EPA. Madigan has long supported the Clean Power Plan and the legal actions that led to it. The Attorney General also recently joined a broad coalition of states and localities in support of the Paris climate change agreement called the "We are Still In" coalition.

Joining Madigan in issuing today's letter are attorneys general from: California, Connecticut, Iowa, Maine, Maryland, Massachusetts, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Vermont, Washington, and the District of Columbia, as well as the California Air Resources Board and the City of Chicago.